Traffic recorder for telephone systems



'Oct. 13,1925.

A. B. SMITH TRAFFIC RECORDER FOR TELEPHONE SYSTEMS Filed Sept. 1. 1921Irmrc? v fiffhur'Bssss SW11 Z,

Patented Oct. 13, 1925.

UNITED STATES ARTHUR BESSEY SMITH, OF EVANSTON, ILLINOIS, ASSIGNOR TOAUTOMATIC ELEC- TRIC COMPANY. OF CHICAGO. ILLINOIS, A

CORPORATION OF ILLINOIS.

TRAFFIC RECORDER FOR TELEPHONE SYSTEMS.

Application filed September 1, 1921. Serial No. 497,773.

T 0 all 'u'lwm it may concern:

Be it known that I, ARTHUR Bnssnr SMITH, a citizen of the United Statesof America, and a resident of Evanston, Cook County, and State ofIllinois, have invented certain new and useful Improvements in TrafiicRecorders for Telephone Systems, of which the following is aspecification.

The present invention relates in general to traffic recorders fortelephone systcms. More Specifically, the invention is concerned withdevices which record the traftic on trunks extending between automaticswitches.

An object of the invention is to provide a metering device upon whichthe number of busy trunks in a certain group is registered automaticallyat periodic intervals, this metering device being adapted for useregardless of the kind of trunks over which the traflic is to berecorded.

The manner in which these and other ob j ects of the invention arecarried out will be described in detail hereinafter with reference tothe accompanying drawing, in which there is diagrammatically shownsufficient t-runk apparatus and circuit arrangements for'enabling theinvention to be readily understood.

Referring now to the drawing; the conductors 1012, inclusive, show atrunk line terminating in a selector switch E. This selector is a switchof the usual Strowger vertical and rotary type having access to linesleading in other selector switches, connector switches, or repeatersdepending upon the size of the system and also upon whether the selectorE has access to trunk lines extending to other oflices. The bankcontacts associated with one of these trunk lines are shown in thedrawing and are indicated by reference characters 100 102, inclusive.

At M is shown the traflic recorder proper. It consists of two rotaryswitches C and C of the same general mechanical construction as that ofthe well known rotary line switches. The rotary switch on the left ofthe figure has two wipers 68 and 64,

together with contact banks adapted to be engaged by them. To the bankcontacts adapted to be engaged by the wiper 64 are connected conductorswhich lead to therelease trunk conductors of the several trunks n thegroup to be metered. Thus, in the drawing, the release trunk conductor11 of the trunk comprising conductors 1012, inclusive, is connected inany convenient manner to the contact 60 ofthe contact bank adapted to beengaged by wiper 64. Similarly, the conductors from the other bankcontacts engaged by wiper '64 are connecttiild to the other releasetrunk conductors in e contact bank adapted to be engaged by the wlper 64has only ten contacts bu obviously, this may be increased if the traificof a larger group of trunks is desired to be recorded by providing arotary switch havlng a greater number of bank contacts.

At T is indicated a constantly operat- 1ng timing mechanism of any wellknown construction which has the function of grounding the conductor 87at periodic intervals. These intervals determine how often the trunks ofthe group are tested in order to'ascertain how many are busy. Thls maybe every minute or at any other convenient. intervals.

The rotary switch at the right of the drawing serves to 1 control therecording meters, a number of the latter being shown at 110-113,inclusive. 1

Having briefly described the apparatus shown in the drawing, a detaileddescription of its operation will now be given. For this purpose it willbe assumed that the trunk line comprising conductors 1012, inclusive,has been seized by another selector switch or line switch under thecontrol of a calling subscriber. Immediately upon the callingsnbscribers line being extended to the selector E, a circuit iscompleted over the calling line loop for the line relay 15. Relay 15,upon energizing, at armature 25 closes the circuit of the slow actingrelay 16. The latter relay, upon operating, at armature 27 prepares theoperating circuits of the selector E and at armature 26 places groundupon the release trunk conductor 11 thereby establishing a holdingcircuit for the preceding switch or switches in. the usual manne Thecallin subscriber may now. operate his calling twice in accordance withthe neit digit'of his desired number. By this same group. In thedrawing, the

operation a series of interruptions is produced in the circuit of theline relay 15, which retracts its armature a corresponding number oftimes. At each retraction of its armature 25 an impulse of current issent over a circuit extending from ground,

by way of back contact and armature 38, armature 25 and its backcontact, armature 27 and its front contact, through the winding of theslow acting relay 17, and thence through the winding of vertlcal magnet42 to battery. Magnet 42, operates to raise the switch wipers 47-49,inclusive, step by step until they are placed opposite the level of bankcontacts corresponding to the digit dialed. The slow acting relay 17 isenergized in series with the vertlcal magnet and at its armature 30prepares a circuit which is completed upon the first upward movement ofthe switch shaft by the engagement of oft-normal spring 33 withits'working contact. This circuit may be traced from ground on releasetrunk conductor 11, by way of armature 30 and its front contact,oil-normal spring 33 and its working contact, and through the winding ofthe stepping relay 18 to battery The relay 18 is energized over thiscircuit and, upon operating, establishes a locking circuit for itself atarmature 31, which includes the interrupter contact of the rotarymagnet, and at armature 32 prepares the circuit of the rotary magnet.Shortly after the termination of the vertical movement of the switch theslow acting relay 17 deenergizes and comletes the circuit of the rotarymagnet 44.

agnet 44 operates to rotate the switch wipers into engagement with thefirst set of bank contacts in the selected level and at its armature 34opens the locking circuit of the interrupter relay 18. The latter relaydeenergizes opening the energizing circuit of the rotary magnet whichdeenergizes also. The further operation of the selector E depends uponwhether or not the trunk line with which the switch wipers are now inengagement is busy. Assuming this trunk line is busy, there will be aground potential placed upon the test contact engaged by the test wiper48. A circuit is thereby completed extending from the said grounded testcontact by way of test wiper 48 for the stepping relay 18. The relay 18is immediately energized over this circuit and operates to establish alocking circuit for itself and to complete the circuit of the rotarymagnet. Magnet 44 rotates the switch wipers into engagement with thenext set of bank contacts in the selected level and, at armature 34,breaks the locking circuit of the stepping relay 18 which deenergizesopening the circuit of the rotary magnet which deenergizes also. Thealternate operation of the stepping relay 18 and the rotary magnet 44will continue until the switch wipers are rotated into engagement withthe set of bank contacts associated with an idle trunk line which, wewill assume, are the bank contacts 100102, inclusive.- When this occursthere will be no ground potential placed upon the testcontact 101 enaged by the test wiper 48 and no circuit willbe completed for thestepping relay 18. Switching relay 19, being no longer short circuited,is energized in series with the said interrupter relay. Upon operating,relay 19 at armature 38 opens the circuit of the slow acting relay 16,at armature 37 places ground upon the test contact 101 in order toprevent the selected trunk line being seized by another selector switchand at armatures 36 and 39 extends the incoming trunk conductors 10 and12 by way of wipers 47 and 49, bank contacts 100 and 102 to the linerelay of the selected switch.

The line relay of this switch is immediately energized and, uponoperating, closes the circuit of the assoclated slow acting releaserelay. The latter relay, upon energizing, prepares certain operatingcircuits in the selected switchand places ground upon the release trunkconductor which terminates in the bank contact 101. When ground isplaced upon the test contact 101 a holding circuit is established forthe switching relay 19 of the selector E in order to maintain thlsselector switch in its operated position. A branch of this holdingcircuit joins the previously traced holding circuit and serves tomaintain the preceding operated switches in their operated position. Thefurther extension of the connection to the desired called line will takeplace in the usual manner and, as this extension does not concern thepresent invention, it will not be described herein.

It will be noted that immediately upon the selector E being seized,ground is placed upon the release trunk conductor 11. By this operationthe bank contact 60 in the contact bank engaged by wiper 64 of therotary switch C is grounded.

The operation of the selector E has been described merely for thepurpose of show? ing how ground is applied to release. trunk conductorsof the various trunk lines and the operation of the trafiic recorderproper will now be gone into. From the above explanation of theoperation of the selector E it will be apparent that for each trunk linebusy in the group there will be a ground potential upon its associatedcontact in the bank of the rotary switch C. In order to start thetraflic recorder M operating, the double pole switch S comprising theblades 85 and 86 is thrown into operated position. As soon as thisoccurs a circuit is completed which extends from ground by way of blade85 of the switch S, conductor 115, resistance 83, back contact andarmature 91, and

motor magnet is not operated over this circuit as it does not receivesufiicient current to operate in series with the resistance 83 though itpartially energizes. This provision is made so as tosecure promptoperation of the magnet when its main circuit is closed. It will benoted that ground on conductor 115 is connected to the wiper 68 of therotary switch C and extends by way of bank contact 116, armature 67 andits back contact to the multiply connected contacts of the bank in therotary switch 0' adapted to be engaged by wiper 92.

When the timing mechanism T operates to momentarilyground the motormagnet 74, the magnet energizes, and when its circuit is broken advancesthe switch wipers 64 and 68' one step into engagement with the contacts60 and 61. A circuit is completed extending from the grounded contact 60associated with the release trunk of the selector E, by way of backcontactand armature 76, andthrough the winding of the motor magnet 90 ofthe'rotary switch C to battery. Magnet 90 operates to rotate the switchwipers 92 and from their normal position and into engagement with bankcontacts 93 and 96.

It will be noted that all the bank contacts except the one innormalposition adapted to be engaged by wiper 68 are multiplied and areconnected to the motor magnet 74 by way of the interrupter s ring 75.and to the slow acting relay 65. onsequently as soon as the wiper 68engages the bank contact 61 the slow acting relay 65 is energized toprepare certain circuits as will appear later, and. the motor magnet 74as it is supplied ground by way of the said wiper, will operate as abuzzer to advance the switch wipers 64 and 68 of the switch C step bystep until they are placed in normal position. For each busy trunk linein the group there will be a ground potential present upon itsassociated contact in the bank ofthe rotary switch C engaged by thewiper 64 and the motor magnet 90 of the rotary switch C will be operatedto advance the switch wipers 92 and 95 one step. Thus, assuming thatthere are eight busy trunks in the group, the wipers of the rotaryswitch C? will be rotated seven more steps'that is into engagement withcontacts and 98. As the slow acting relay 65 is connected in multiplewith the rotary magnet 74 to the bank contacts engaged by the wiper 68it maintains its armature attracted throughout the rotation of theswitch C. When the wiper 68 of the switch 0 rotates into normal positionthe circuit of the motor magnet 74 is opened and the rotation of theswitch C ceases. The circuit of the slow acting relay 65 is also openedbut before the deenergization of-this relay a circuit. is completedextending from ground on conductor 115, by way of wiper 68, bank contact116,

armature 67 and its working contact, wiper 95 of the rotary switch C,contact 98, and thence through the winding of the meter 112 to battery.As was mentioned before, when the wiper 68 is rotated into normalposition the circuit of the slow acting relay 65 is opened and after ashort interval this relay deenergizes. A circuit is thereby completedextending from grounded conductor 115, wiper 68, bank contact 116,armature 67 and its back contact, conductor 94, multi-' ply connectedbank contacts adapted to be engaged'by wiper 92, said wiper, backcontact of armature 91 and said armature, and thence through the windingof the motor magnet 90 to battery. The motor magnet 90 now operates as abuzzer to advance the switch wipers 92 and 95 into their normal positionas the bank contact in normal position is not connected in multiple withthe other bank contacts adapted to be engaged by wiper 92 and istherefore ungrounded. In above manner the switches C and C are restoredto normal.

The foregoing operations all occur in response to the first impulse ofground on the conductor 87 after the double pole switch S has beenthrown and take but an exceedingly short .interval of time. When groundis again placed on conductor'87 by the timing mechanism T-the sameoperations again take place, that is, the rotary switch G is operated totest all the trunk lines in the group and the rotary switch C isoperated first until the wiper 95 is associated with the proper meterwhich corresponds to the number of busy trunks in the group, andthereafter is restored to normal position. These operations continue totake place each time ground is placed on conductor 87 by the operationof the timing mechanism, and each time they take place the metercorresponding to the number of trunks busy at that time is actuated.

From the above it will be seen that the various meters such as'110, 111,112 and 113 show a complete record of the number of trunks that arebusyin the group at the various intervals which are determined by I theoperation of the timing mechanism and which may be set 'for anyconvenient periods. In the drawing only four meters have been shown andthese are connected to the last contacts of'the set adapted to beengaged by wiper 95 as usually it is only desirable to find out thetraflic when a group of trunks becomes overloaded or nearly so. It willbe understood, of course, that the other contacts in the bank adapted tobe engaged by wiper 95 may be connected to meters in the same manner asshown with the meters illustrated if it is desirable to record whenthere are a small number of trunks in the group busy.

The operation of the trafiic recorder has been described with referenceto a trunk line terminating in a selector switch but it will beperfectly clear that the device will record equally well the traiiic onvarious other types of trunk lines.

The features of the invention having been described and ascertained,what is thought to be new and desired to have protected by LettersPatent, will be brought out in the appended claims.

What I claim as my invention is:

1. In a telephone system, a group of trunk lines, means for making anynumber of said trunk lines busy, and means operated and reoperatedautomatically for recording at intervals the exact number of busy trunklines in said group regardless of the number of trunk lines busy.

2. In a telephone system, a group of trunk lines terminating inautomatic switches, means for seizmg said trunk lines and for'trunklines. means for making any trunk hne 1n sald group busy, a rotarySWlth,'

means for operating said switch to test all the trunk lines in saidgroup whether they are all busy or not, means controlled by said switchfor recording the number of busy trunk lines in said group, and meansincluding a timing device for causing the testing and recordingoperations to be repeated at regular intervals.

5. In a telephone system. a group of trunk-lines, means for making saidtrunk lines busy when they are in use, a rotary switch, automatic meansfor operating said switch to test all of the trunk lines in said groupat regular periodic intervals, and means controlled by said switch forrecording thenumber of busy trunk lines in sa1d group every time thesaid trunk lines are tested.

6. In a telephone system, a. group of trunk lines, means for making anytrunk line in said group busy, a rotary switch,

, automatic means for operating said switch to test all of the trunklines in said group at periodic intervals, a plurality of meters, eachof said meters corresponding to a ditferent number of busy trunk lines,and

bank contacts being connected to one of said release conductors, meansfor automatically operating and reoperating said switch to test saidrelease conductors whether grounded or not by means of said wiper, andmeans controlled by said switch for recording the number of busy trunklines in said group every time the switch is operated.

8. In a telephone system, a group of trunk lines terminating inautomaticswitches, release conductors for the said trunk lines, means for makingany trunk line in said group busy by placing ground upon its releaseconductor, a rotary switch, a wiper for said switch, bank contactsadapted to be engaged thereby, each of said bank contacts beingconnected to one of said release conductors, means for automaticallyoperating said switch to test said release conductors by means of saidwiper, a group of meters,

means controlled by said wiper for selecting the meter corresponding tothe number of busytrunk lines in said group, and means for thenactuating the selected meter.

9. In a telephone system, a group of trunk lines, means for making anyof said trunk lines busy, a rotary switch, means operative for causingsaid switch to test said group of trunk lines, a second rotary switch,means for operating said second switch one step for each busy trunkencountered in said testing operation, and means associated with saidswitches operative after said group of trunks have been tested forrecording the number of busy trunks in said group.

10. In a telephone system, a group of trunk lines, means for making anyof said trunk lines busy, a rotary switch, means operative for causingsaid switch to test said group of trunk lines, a second rotary switch,means for operating said second switch one step for each busy trunkencountered in said testing operation, a wiper and bank contact set forsaid second switch, a meter connected to each bank contact of said set,and means operative after the testing is completed for actuating themeter connected to the bank contact engaged by said wiper.

11. In a telephone system, a group of trunk lines,'a group of meters,said meters meters to record the number group of trunk corresponding innumber to the number of trunk lines in said group,) each meterrepresenting' a diife'rent num er of busy trunk lines means for makinganynumber of said trunk lines busy, said busy lines interspersedpromiscuously amongst idle trunk lines, and means for. operating thecorrect one of said of busy trunk lines in said group.

12. In a telephone system, .a group of trunk lines, a group of meters,-each of said meters representing a different number of busy trunk lines,means for .makmg sald trunk lines busy, the busy trunk lines lkinginterspersed promiscuously amongst 'idle' trunk lines at any giveninstant, and auto-' matic means operated at periodic intervals foroperating certain of said meters to suecessively record the number ofbusy trunk lines in said group. p

13. In a telephone system including a group of trunk lines in which busyand idle trunk lines are interspersed promiscuously amongst each other,a group of meters, each of said meters representing a different numberof busy trunk lines, and means for operating the correct one of saidmeters to record the number of busy trunk lines in said group. ,4

14. In a telephone system including a group of trunklinesin which busyand idle trunk lines are interspersed promiscuously amongst each other,meters, each of said meters representing a difierent number of busytrunk lines, and automatiic means operated at periodic intervals foroperating certain of said meters to successively record the number ofbus trunk lines in said group. 7 15. In a telbphone system including alines in which there are idle and busy trunk lines, a group of meters,said meters representing progressively greater pluralities of busy trunklines, respectively, and means for operatin the correct one of saidmeters to record t e number of busy trunk lines in'said group.

16. The combination, in a trafiic recorder for telephone trunkingsystems, of means for repeatedly testing all the trunks in a group, andmeans for counting the number of times each of a number of differentpluralities of said trunk lines are found busy.

17. The combination, in a trafiic recorder for telephone trunkingsystems, of means for repeatedly testing all the trunks in a group, andmeans inactive during testing but operated each time when the testing ofthe group is completed for recording the number of trunk lines foundbusy, whether all of said trunk lines are busy or not.

18. The combination, in a trafiic recorder for telephone trunkingsystems, of means 'for testing all the busy and idle trunks ina group,one at a time, means for automatically repeating the testing operation aplut'runk lines vof the succeeding meters representing a' trunk lines,means for making lines, means for making any trunk line in said groupbusy by placing ground upon the release conductor corresponding to saidtrunk line, a rotary switch, a wiper for said switch, bank contacts adated to be engaged thereby, each of said bank contacts being connected toone of said release conductors, means for automatically startingtheoperation of said rotary switch, circuit arrangements the operationof said rotary switch to test said release conductors by means of saidwiper, a second rotary switch under the 'oint control of said firstrotary switch an the busy condition of said release conductors, saidsecond rotary switch operated once for every busy trunk line, aplurality of meters associated with the bank contacts of said secondrotary switch, each of said meters representing a different number ofbusy trunk lines, and circuit arrangements associated with said switchesfor operating the meter corresponding to the number of busy trunk lines.

20. In a telephone system including a group of trunk lines in whichthere are busy and idle trunk lines, a plurality of meters, one of saidmeters representing a certain plurality of busy trunk lines, the nextmeter representing a greater plurality of busy than said first meter,and each greater. plurality of busy trunk lines than the meterimmediately preceding it, and meter operating means rendered effectiveat intervals, the meter operated each time being dependent upon thenumber of trunk lines busy. y

21. In a telephone system, a group of any of said trunk lines busy, arotary switch having a normal position, means operative for causing saidswitch to advance from its normal position to test said group of trunklines and to return to its normal position, a second rotary switch,means for operating said second switch one step for each busy trunkencountered in said testing operation, and means associated with saidswitches and operative after the first named switch has position forrecording returned to its normal the number of busy trunks in saidgroup.

22. In a telephone system, a group of trunk lines, means for making anyof said trunk lines busy, a rotary switch having a normal position,means for operating said switch from its normal position to test saidgroup oftrunk lines and for returning the said switch to its normalposition, a second rotary switch also havin a normal position,

means for operating sai second swltch one I step for each busy trunkencountered in said testing operation, means associated with said Iswitches and operative after said first switch has returned to itsnormal position for recording the number of busy trunks in said group,and means for thereupon returning said second rotary switch to itsnormal position. In witness whereof, I hereunto subscribe," my name this21st day of August, A/Dq ARTHUR BESSEY SMITH.

